Lighting devices with a light source, a reflector encompassing the light source, and a lens mounted in front of the reflector, are known. Such lighting devices generally have a light source such as a filament lamp, a halogen lamp or the like, and are so dimensioned that the light source represents approximately a point light source in relation to the reflector and the lens.
Known from each of DE 298 04 248 U1, DE 199 01 391 A1, DE 86 22 788 U1 and U.S. Pat. No. 2,282,167 are lighting devices, in particular headlights, in which the aperture angle of the light ray bundle may be adjusted by shifting the optical elements (lenses).